The present invention is directed generally to electrical switching devices, and more particularly, the present invention is directed to a switch joint positionable between a pair of pressure-activated electrical switching mats.
Various types of pressure-activated or pressure-sensitive electrical switching devices are known in the art. Switching devices of this type may take many forms and may be embodied in various structures. For example, elongate ribbon switches may be used as window sill alarms or road switches. Switching devices may be incorporated into structures such as passenger seats, activating when the passenger sits in the seat, and also into floor mats used for security or other purposes, to detect movement of objects or pedestrian traffic thereover. Examples of such switching devices are evident in prior patents.
U.S. Pat. Nos. 2,896,042; RE 24,541; 3,142,224; 3,694,600; 3,710,054 and 3,717,735; each to Koenig, show various constructions of electrical ribbon or tape switches. These switches generally include a pair of spaced conductors supported in an insulative jacket. Relatively light pressure on the jacket forces the conductors into electrical engagement, thereby activating the switch.
Electrical pressure-actuated or pressure-sensitive switches have been incorporated into numerous designs of floor mats. The mat design itself may be varied for particular applications. Examples of such pressure-actuated electrical switching mats are also shown in prior patents.
U.S. Pat. No. 2,938,977 to Koenig shows an electrical switching mat having a bottom insulating sheet, a plurality of upper and lower electrical contact strips which are normally electrically isolated, and an upper insulating sheet overlying the contact strips. Pressure on the mat forces the upper and lower contact strips into electrical engagement, activating the electrical switch.
U.S. Pat. No. 3,243,540 to Miller discloses a pressure-actuated electrical switching mat including compressible protective layers made of foam rubber.
U.S. Pat. Nos. 5,001,312 and 5,142,109, each issued to O'Meara, Jr. et al., show a pressure-actuated electrical switching mat having a moisture resistant switching chamber. This switching chamber is protected by a puncture resistant protective layer.
Many of the pressure-actuated electrical switching mats presently in use generally include a major planar pressure-sensitive surface defining an active area. Pressure applied to the mat at this active area, for example by pedestrian traffic or movement of objects thereover, activates the switching device contained in the mat. However, mats of this type also typically include a perimetrical boundary or edge which is nonpressure-sensitive. This pressure-inactive edge, while relatively small in comparison to the active pressure-sensitive surface, still provides an area which, when subjected to pressure, will not activate the switching device contained within the mat. The expanse of the inactive area is multiplied where several mats are used in juxtaposition in situations where it is desired to increase the sensing area. By abutting the inactive edges of the mats adjacent one another, the inactive area may be wide enough so that certain pedestrian traffic or movement of objects may not be detected. This results in the mats not producing the desired effect, i.e., the detection of movement of objects or people thereacross.